diff --git a/configure.ac b/configure.ac
index 02151543..ba0409a5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -243,6 +243,7 @@ if test "x$GCC" = "xyes" ; then
   JE_CFLAGS_ADD([-Wshorten-64-to-32])
   JE_CFLAGS_ADD([-Wsign-compare])
   JE_CFLAGS_ADD([-Wundef])
+  JE_CFLAGS_ADD([-Wno-format-zero-length])
   JE_CFLAGS_ADD([-pipe])
   JE_CFLAGS_ADD([-g3])
 elif test "x$je_cv_msvc" = "xyes" ; then
diff --git a/include/jemalloc/internal/jemalloc_internal_macros.h b/include/jemalloc/internal/jemalloc_internal_macros.h
index 4571895e..ed75d376 100644
--- a/include/jemalloc/internal/jemalloc_internal_macros.h
+++ b/include/jemalloc/internal/jemalloc_internal_macros.h
@@ -37,4 +37,7 @@
 #  define JET_MUTABLE const
 #endif
 
+#define JEMALLOC_VA_ARGS_HEAD(head, ...) head
+#define JEMALLOC_VA_ARGS_TAIL(head, ...) __VA_ARGS__
+
 #endif /* JEMALLOC_INTERNAL_MACROS_H */
diff --git a/include/jemalloc/internal/log.h b/include/jemalloc/internal/log.h
index 1df8cfff..5ce8c354 100644
--- a/include/jemalloc/internal/log.h
+++ b/include/jemalloc/internal/log.h
@@ -2,14 +2,17 @@
 #define JEMALLOC_INTERNAL_LOG_H
 
 #include "jemalloc/internal/atomic.h"
+#include "jemalloc/internal/malloc_io.h"
 #include "jemalloc/internal/mutex.h"
 
 #ifdef JEMALLOC_LOG
-#  define JEMALLOC_LOG_BUFSIZE 1000
+#  define JEMALLOC_LOG_VAR_BUFSIZE 1000
 #else
-#  define JEMALLOC_LOG_BUFSIZE 1
+#  define JEMALLOC_LOG_VAR_BUFSIZE 1
 #endif
 
+#define JEMALLOC_LOG_BUFSIZE 4096
+
 /*
  * The log_vars malloc_conf option is a '|'-delimited list of log_var name
  * segments to log.  The log_var names are themselves hierarchical, with '.' as
@@ -41,7 +44,7 @@
  * statements.
  */
 
-extern char log_var_names[JEMALLOC_LOG_BUFSIZE];
+extern char log_var_names[JEMALLOC_LOG_VAR_BUFSIZE];
 extern atomic_b_t log_init_done;
 
 typedef struct log_var_s log_var_t;
@@ -84,11 +87,36 @@ if (config_log) {							\
 	}								\
 }
 
-#define log(log_var, format, ...)					\
+/*
+ * MSVC has some preprocessor bugs in its expansion of __VA_ARGS__ during
+ * preprocessing.  To work around this, we take all potential extra arguments in
+ * a var-args functions.  Since a varargs macro needs at least one argument in
+ * the "...", we accept the format string there, and require that the first
+ * argument in this "..." is a const char *.
+ */
+static inline void
+log_impl_varargs(const char *name, ...) {
+	char buf[JEMALLOC_LOG_BUFSIZE];
+	va_list ap;
+
+	va_start(ap, name);
+	const char *format = va_arg(ap, const char *);
+	size_t dst_offset = 0;
+	dst_offset += malloc_snprintf(buf, JEMALLOC_LOG_BUFSIZE, "%s: ", name);
+	dst_offset += malloc_vsnprintf(buf + dst_offset,
+	    JEMALLOC_LOG_BUFSIZE - dst_offset, format, ap);
+	dst_offset += malloc_snprintf(buf + dst_offset,
+	    JEMALLOC_LOG_BUFSIZE - dst_offset, "\n");
+	va_end(ap);
+
+	malloc_write(buf);
+}
+
+/* Call as log(log_var, "format_string %d", arg_for_format_string); */
+#define log(log_var, ...)						\
 do {									\
 	log_do_begin(log_var)						\
-		malloc_printf("%s: " format "\n",			\
-		    (log_var).name, __VA_ARGS__);			\
+		log_impl_varargs((log_var).name, __VA_ARGS__);		\
 	log_do_end(log_var)						\
 } while (0)
 
diff --git a/include/jemalloc/internal/malloc_io.h b/include/jemalloc/internal/malloc_io.h
index 47ae58ec..4992d1d8 100644
--- a/include/jemalloc/internal/malloc_io.h
+++ b/include/jemalloc/internal/malloc_io.h
@@ -53,6 +53,10 @@ size_t malloc_vsnprintf(char *str, size_t size, const char *format,
     va_list ap);
 size_t malloc_snprintf(char *str, size_t size, const char *format, ...)
     JEMALLOC_FORMAT_PRINTF(3, 4);
+/*
+ * The caller can set write_cb and cbopaque to null to choose to print with the
+ * je_malloc_message hook.
+ */
 void malloc_vcprintf(void (*write_cb)(void *, const char *), void *cbopaque,
     const char *format, va_list ap);
 void malloc_cprintf(void (*write_cb)(void *, const char *), void *cbopaque,
diff --git a/src/jemalloc.c b/src/jemalloc.c
index 48a268ff..1dc66823 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -2364,7 +2364,7 @@ je_free(void *ptr) {
 		}
 		check_entry_exit_locking(tsd_tsdn(tsd));
 	}
-	log(log_core_free_exit, "%s", "");
+	log(log_core_free_exit, "");
 }
 
 /*
@@ -2957,7 +2957,7 @@ je_dallocx(void *ptr, int flags) {
 	}
 	check_entry_exit_locking(tsd_tsdn(tsd));
 
-	log(log_core_dallocx_exit, "%s", "");
+	log(log_core_dallocx_exit, "");
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
@@ -3024,7 +3024,7 @@ je_sdallocx(void *ptr, size_t size, int flags) {
 	}
 	check_entry_exit_locking(tsd_tsdn(tsd));
 
-	log(log_core_sdallocx_exit, "%s", "");
+	log(log_core_sdallocx_exit, "");
 }
 
 JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW
@@ -3083,7 +3083,7 @@ je_mallctl(const char *name, void *oldp, size_t *oldlenp, void *newp,
 	check_entry_exit_locking(tsd_tsdn(tsd));
 	ret = ctl_byname(tsd, name, oldp, oldlenp, newp, newlen);
 	check_entry_exit_locking(tsd_tsdn(tsd));
-	
+
 	log(log_core_mallctl_exit, "result: %d", ret);
 	return ret;
 }
@@ -3124,7 +3124,7 @@ je_mallctlbymib(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
 	static log_var_t log_core_mallctlbymib_exit = LOG_VAR_INIT(
 	    "core.mallctlbymib.exit");
 
-	log(log_core_mallctlbymib_entry, "%s", "");
+	log(log_core_mallctlbymib_entry, "");
 
 
 	if (unlikely(malloc_init())) {
@@ -3150,13 +3150,13 @@ je_malloc_stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 	static log_var_t log_core_malloc_stats_print_exit = LOG_VAR_INIT(
 	    "core.malloc_stats_print.exit");
 
-	log(log_core_malloc_stats_print_entry, "%s", "");
+	log(log_core_malloc_stats_print_entry, "");
 
 	tsdn = tsdn_fetch();
 	check_entry_exit_locking(tsdn);
 	stats_print(write_cb, cbopaque, opts);
 	check_entry_exit_locking(tsdn);
-	log(log_core_malloc_stats_print_exit, "%s", "");
+	log(log_core_malloc_stats_print_exit, "");
 }
 
 JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW
diff --git a/src/log.c b/src/log.c
index 022dc584..778902fb 100644
--- a/src/log.c
+++ b/src/log.c
@@ -3,7 +3,7 @@
 
 #include "jemalloc/internal/log.h"
 
-char log_var_names[JEMALLOC_LOG_BUFSIZE];
+char log_var_names[JEMALLOC_LOG_VAR_BUFSIZE];
 atomic_b_t log_init_done = ATOMIC_INIT(false);
 
 /*
@@ -59,7 +59,7 @@ log_var_update_state(log_var_t *log_var) {
 	while (true) {
 		const char *segment_end = log_var_extract_segment(
 		    segment_begin);
-		assert(segment_end < log_var_names + JEMALLOC_LOG_BUFSIZE);
+		assert(segment_end < log_var_names + JEMALLOC_LOG_VAR_BUFSIZE);
 		if (log_var_matches_segment(segment_begin, segment_end,
 		    log_var_begin, log_var_end)) {
 			atomic_store_u(&log_var->state, LOG_ENABLED,
diff --git a/test/unit/log.c b/test/unit/log.c
index 6db256f1..053fea41 100644
--- a/test/unit/log.c
+++ b/test/unit/log.c
@@ -170,13 +170,25 @@ TEST_BEGIN(test_logs_if_no_init) {
 }
 TEST_END
 
+/*
+ * This really just checks to make sure that this usage compiles; we don't have
+ * any test code to run.
+ */
+TEST_BEGIN(test_log_only_format_string) {
+	if (false) {
+		static log_var_t l = LOG_VAR_INIT("str");
+		log(l, "No arguments follow this format string.");
+	}
+}
+TEST_END
+
 int
 main(void) {
-
 	return test(
 	    test_log_disabled,
 	    test_log_enabled_direct,
 	    test_log_enabled_indirect,
 	    test_log_enabled_global,
-	    test_logs_if_no_init);
+	    test_logs_if_no_init,
+	    test_log_only_format_string);
 }